Which 300mm Dagor for 12x20?

Inspired by the dagor thread, I remember reading somewhere(probably the LF forum) that some 300mm dagors will cover 12x20. The only problem is I have no clue as to which ones are up to the task. If anybody has any hints that would be great!

Thanks.

Gary

Build a man a fire and he will be warm for hours.
Set a man on fire and he will be warm for the rest of his life.

Thanks, I had suspected it would be the older dagors that covered. I had read the Gold Ring/Dot Dagors had alot less coverage than their older counter parts. That is a shame really, my favorite 8x10 lens is my 14 inch Gold Dot Kern Dagor.....I really wish it would cover 12x20.

Gary

Build a man a fire and he will be warm for hours.
Set a man on fire and he will be warm for the rest of his life.

While we wait for the Dagor experts to arrive, here's a hint: older. Much older.

Depending on when and how they were manufactured Dagors of the same focal length vary quite a bit in coverage. I have seen 14" and 16.5" Dagors that would not cover 12X20, but I once owned a very old one that threw a circle of illumination large enough for 12X20, but of course I had to stop down to f/64 to get decent performance on the corners, and even that was not all that good. The serial number of the 12" Dagor that I had that covered 12X20 suggested that it was made in the 1920s so Oren is right in that you should think older rather than newer.

Gary....You might want to get one of my Fuji 300 lenses that I finally got mounted in a Copal 3 by Grimes. It does not quite cover the corners wide open but the coverage is mighty. You would end up with about a contact 11x19 which is still nice. They are all in barrel. Just mount in a board and use the cap. It is a fixed f8 so you could go from there with exposure. Let me know if you are interested........................Tav

At one point or another we all have a tendency to get inspired by Mr. Dagor.

When we finally locate one and put it to use we quickly find an excuse to sell it to someone that is a bit behind us in the "dagor mystique" curve. I have seen the cycle repeat itself regularly.

When I was recently working on a lens project with an optical physicist and mentioned the Dagor he looked back at me like he had just bitten into a lemon. "Surely we can do much better than that," he commented. He showed me the curves and pointed out the deficiencies of the design and we moved on. The project was doomed when we got to the materials cost but I got a real taste about what technological advancements in optical glass and computerized design programs have done to dramatically improve the process of lens design. Bottom line from my point of view - there are many other alternatives that are much less costly and perform much better.

I have sold off most of my Dagor type lenses so mostly agree with your comments. Modern plasmat type lenses are sharper at large apertures than Dagors, and probably have better coating.

However, the design itself did not reach the end of the line in the 1970s with the multi-coated Kern dagors, which are some of the most contrasty lenses ever made. The fairly recent Schneider 550mm XXL Fine Art lens is in fact a true Dagor design which takes advantage of new glasses and computer design. So with all the background of lens design Schneider chose a Dagor type design as the one that best delivered the specific image qualities they thought important in a lens of this type.

It is convertible of course, but how good it is converted I really don't know. In the early days all Dagors were sold as convertible lenses even though the single elements were not fully corrected. They were ok for portrait use but did not produce sharp landscapes. I once had an old 19" Dagor and use it in convertible mode. It had a lot of chromatic aberrations and was not really useful unless you use amn orange filter to block most of the red light.

Sandy King

Last edited by sanking; 02-06-2010 at 10:00 AM. Click to view previous post history.